Top Loaded Washing Machine having Drum with Horizontal Axis of Rotation

ABSTRACT

A washing machine includes a tub fixedly installed in a cabinet, a drum rotatably installed in the tub for containing laundry and provided with an opening formed through the outer circumferential surface thereof so that the laundry is taken into and out of the drum through the opening. A drum door is provided at the opening of the drum and moves in the circumferential direction of the drum relative to the drum to open and close the opening of the drum. A driving unit rotates the drum.

This application is a Continuation of co-pending application Ser. No.11/265,273, filed on Nov. 3, 2005, and for which priority is claimedunder 35 U.S.C. §120 and which claims the benefit of Korean PatentApplication No. 10-2004-0089834, filed on Nov. 5, 2004, which is herebyincorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a washing machine, and moreparticularly, to a washing machine having a structure such that laundryis conveniently taken into and out of the washing machine.

2. Discussion of the Related Art

Generally, a washing machine performs washing, rinsing, and dehydratingoperations by filling the lower portion of the inside of a tub withwater and detergent, placing laundry into a drum installed in the tub,and rotating the drum.

Such a washing machine is an apparatus for eliminating dirt from thelaundry using proper detergent and mechanical force.

Particularly, a drum washing machine, in which a drum is horizontallyinstalled in a tub, washes laundry by rotating the drum by means of thedriving force of a motor. Accordingly, the drum washing machine does notcause entanglement of the laundry and damage to the laundry, consumes asmall quantity of washing water, and exerts beating and rubbing effects.

It is necessary to conveniently take laundry into and out of the abovewashing machine. Accordingly, the development of a washing machinehaving a structure such that laundry is conveniently taken into and outof the washing machine is required.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a washing machinehaving a structure such that laundry is conveniently taken into and outof the inside of the washing machine.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, awashing machine comprises a tub fixedly installed in a cabinet; a drumrotatably installed in the tub for containing laundry, and provided withan opening formed through the outer circumferential surface thereof sothat the laundry is taken into and out of the drum through the opening;a drum door provided at the opening of the drum, and moving in thecircumferential direction of the drum relatively to the drum to open andclose the opening of the drum; and a driving unit for rotating the drum.

The drum door rotates centering on a rotary axis of the drum to open andclose the opening of the drum.

Preferably, the drum door is connected to the driving unit toautomatically open and close the opening of the drum.

For this reason, the washing machine further comprises a clutch unit forselectively interconnecting the driving unit and the drum to selectivelytransmit driving force of the driving unit to the drum.

The driving unit comprises a driving motor; and a door driving shaft,one end of which is connected to a rotor of the driving motor and theother end of which is connected to a rotary center of the drum door, totransmit the driving force of the driving motor to the drum door.

The drum comprises a drum driving shaft, one end of which is connectedto a rotary center of the drum and the other end of which is selectivelyconnected to the driving unit by the clutch unit, and being concentricwith the door driving shaft.

The drum door is movable along the inner circumferential surface of thedrum in the circumferential direction, and the door driving shaft passesthrough the drum driving shaft in the axial direction.

The clutch unit is installed between the driving motor and the drumdriving shaft such that the clutch unit moves in the axial direction ofthe drum driving shaft, transmits the driving force of the driving unitto the drum driving shaft so that the drum driving shaft is rotatedsimultaneously with the rotation of the door driving shaft, when thewashing machine is operated in washing and dehydration modes, andinterrupts the transmission of the driving force of the driving motor tothe drum driving shaft, when the drum door is opened.

For this reason, the clutch unit comprises a coupler installed betweenthe driving motor and the drum driving shaft such that the coupler movesin the axial direction of the drum driving shaft, to selectivelyinterconnect the drum driving shaft and the door driving shaft; and acoupler driving portion for moving the coupler.

The coupler moves in the axial direction of the drum driving shaft bythe coupler driving portion under the condition that the coupler isconnected to the drum driving shaft by serrations, and is selectivelyconnected to the door driving shaft.

One end of the coupler is separated from the door driving shaft and theother end of the coupler is connected to one end of the tub so that theposition of the opening of the drum is not changed when the drum door isopened.

More specifically, the coupler comprises a first serration formed on oneend of the coupler and selectively connected to a driving serrationformed in the door driving shaft; a second serration engaged with aserration formed in the drum driving shaft; and a third serration formedon the other end of the coupler and selectively connected to a fixingserration formed in one end of the tub.

The coupler driving portion comprises at least one electromagnet formoving the coupler to control the interconnection between the couplerand the door driving shaft.

More specifically, the coupler driving portion comprises at least oneelectromagnet formed on one of the tub and the coupler; a magneticmember formed on the other one of the tub and the coupler for moving thecoupler in one direction by the electromagnetic interaction with theelectromagnet; and an elastic member, one end of which is supported bythe coupler and the other end of which is supported by the rotor of thedriving motor.

The magnetic member moves the coupler when current is applied to theelectromagnet, cuts the interconnection between the coupler and thedriving unit, and interconnects the coupler and one end of the tub so asto prevent the rotation of the drum driving shaft when the drum door isopened.

The washing machine further comprises an alignment unit for aligning theopening of the drum to coincide with an opening formed through the tub.

The washing machine further comprises at least one latching protrusionformed on one edge of the opening of the drum; and at least one latchinghook formed on one edge of the drum door and latched onto the latchingprotrusion when the drum door is closed.

The washing machine further comprises at least one subsidiary latchingprotrusion formed on the other edge of the opening of the drum; and atleast one subsidiary latching hook formed on the other edge of the drumdoor and latched onto the subsidiary latching protrusion.

The washing machine further comprises a weight provided on thesubsidiary latching hook for separating the subsidiary latching hookfrom the subsidiary latching protrusion by its own weight when the drumis stopped and connecting the subsidiary latching hook to the subsidiarylatching protrusion by the centrifugal force when the drum is rotated.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a schematic longitudinal sectional view of a washing machinein accordance with an embodiment of the present invention;

FIG. 2 is a schematic sectional view of the washing machine inaccordance with the embodiment of the present invention;

FIG. 3 is a sectional view of a drum of the washing machine inaccordance with the embodiment of the present invention;

FIGS. 4A and 4B are enlarged views of portions “A” and “B” of FIG. 3;

FIG. 5 is a sectional view of a drum door driving device of the washingmachine in accordance with the embodiment of the present invention;

FIG. 6 is a sectional view of the drum door driving device of thewashing machine in accordance with the embodiment of the presentinvention, when a drum door is driven; and

FIG. 7 is a sectional view of the drum door of the washing machine inaccordance with the embodiment of the present invention, in an openedstate.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

Wherever possible, the same reference numbers will be used throughoutthe drawings to refer to the same or like parts.

First with reference to FIGS. 1 and 2, a washing machine of the presentinvention comprises a cabinet 100 forming the external appearance of thewashing machine, a tub 200 fixedly installed in the cabinet 100, and adrum 300 rotatably installed in the tub 200.

In this embodiment, a laundry inlet port (not shown), through whichlaundry is taken into and out of the cabinet 100, is formed through thecabinet 100, and a foldable cabinet door 110 is rotatably connected toone edge of the laundry inlet port.

The tub 200 contains washing water for washing the laundry. An opening210 opened towards the laundry inlet port is formed through the outercircumferential surface of the tub 200. The opening 210 is opened andclosed by a rotating door or a sliding door (not shown).

Here, the door for opening and closing the opening 210 of the tub 200serves to prevent the outflow of the washing water and to cause thelaundry to be taken into and out of the tub 200.

In this embodiment, in order to allow a user to take the laundry intoand out of the inside of the washing machine from the upper part of thewashing machine, the laundry inlet port is formed through the uppersurface of the cabinet 100, and the opening 210 of the tub 200 is formedthrough the outer circumferential surface of the upper portion of thetub 200.

An opening 310, through which the laundry is taken into and out of thedrum 300, is formed through the outer circumferential surface of the tub300. In addition to the above constitution, the washing machine of thepresent invention further comprises a drum door 400 provided at theopening 310 of the drum 300 for opening and closing the opening 310 ofthe drum 300.

A plurality of through holes for passing the washing water are formedthrough the drum 300 and the drum door 400, and the drum 300 is rotatedby a driving unit 500.

The drum door 400 of the washing machine of the present invention movesin the circumferential direction of the drum 300 relatively to the drum300, thereby opening and closing the opening 310 of the drum 300.

Here, the motion of the drum door 400 in the circumferential directionof the drum 300 relatively to the drum 300 means the motion of the drumdoor 400 in the circumferential direction of the drum 300 under thecondition that the drum 300 is fixed, the rotation of the drum 300 underthe condition that the drum door 400 is fixed, or the rotation of thedrum 300 and the drum door 400 in the opposite directions, so that therelative positions of the drum 300 and the drum door 400 are changed.

Since the drum 300 usually has a cylinder-shaped outer circumferentialsurface, preferably, the drum door 400 has an arc shape.

Accordingly, the drum door 400 slidably moves to open and close theopening 310 of the drum 300, or, as described in this embodiment,rotates centering on a rotary axis of the drum 300 to open and close theopening 310 of the drum 300.

Although this embodiment describes the drum door 400 moves to open andclose the opening 310 of the drum 300 by the driving unit 500 rotatingthe drum 300, the motion of the drum door 400 is not limited thereto.

Here, the opening 310 of the drum 300 is extended in the lengthwisedirection of the drum 300 so that the laundry can be easily taken out ofthe drum 300 through the opening 310.

In addition to the above constitution, the washing machine of thepresent invention further comprises a clutch unit 600 for selectivelyinterconnecting the driving unit 500 and the drum 300, therebyselectively transmitting the driving force of the driving unit 500 tothe drum 300.

The driving unit 500 comprises a driving motor 510 for generating rotaryforce, and a door driving shaft 520 for interconnecting the drivingmotor 510 and a rotary center of the drum door 400.

The driving motor 510 comprises a stator 511 fixed to the tub 200, and arotor 512 rotating around the stator 511.

One end of the door driving shaft 520 is connected to the rotor 512, andthe other end of the door driving shaft 520 is connected to the rotarycenter of the drum door 400. More specifically, the rotor 512, the doordriving shaft 520, and the rotary center of the drum door 400 areintegrally interconnected.

A drum driving shaft 320, which is selectively connected to the drivingunit 500 by the clutch unit 600, is provided at the rotary center of thedrum 300.

More specifically, one end of the drum driving shaft 320 is connected tothe rotary center of the drum 300, and the other end of the drum drivingshaft 320 is selectively connected to the driving unit 500 by the clutchunit 600. Since the drum driving shaft 320 is concentric with the doordriving shaft 520, the drum driving shaft 320 and the door driving shaft520 have a rotary axis in common.

Preferably, the washing machine of the present invention furthercomprises an alignment unit 700 for aligning the opening 310 of the drum300 to a designated position when a user wants to take laundry into orout of the drum 300.

That is, the alignment unit 700 allows the opening 310 of the drum 300to coincide with the opening 210 of the tub 200.

The alignment unit 700 comprises a sensing target portion 710 installedat one side of the outer surface the drum 300, and a position sensor 720installed at one side of the inner surface of the tub 200 so that theposition sensor 720 reacts with the sensing target portion 710.

Accordingly, when the drum 300 is rotated by the driving motor 510 sothat the sensing target portion 710 coincides with the position sensor720, a signal of the position sensor 720 is applied to a controller, andthe controller stops the operation of the driving motor 510 so that theopening 310 of the drum 300 coincides with the opening 210 of the tub200.

Since the laundry inlet port is formed through the upper portion of thecabinet 100 in this embodiment, preferably, the drum 300 is horizontallyinstalled in the tub 200. Accordingly, a washing machine, which will bedescribed hereinafter, denotes a drum washing machine.

With reference to FIGS. 2 and 3, at least one latching protrusion 331 isformed on one edge of the opening 310 of the drum 300. At least onelatching hook 411, which is latched onto the latching protrusion 331when the drum door 400 is closed, is formed on one edge of the drum door400.

Further, at least one subsidiary latching protrusion 332 is formed onthe other edge of the opening 310 of the drum 300. At least onesubsidiary latching hook 412, which is latched onto the subsidiarylatching protrusion 332, is formed on the other edge of the drum door400.

With reference to FIGS. 4A and 4B, in this embodiment, a plurality ofthe latching protrusions 331 are formed on one edge of the opening 310of the drum 300, and a plurality of the subsidiary latching protrusions332 are formed on the other edge of the opening 310 of the drum 300.Further, a plurality of the latching hooks 411 are formed on one edge ofthe drum door 400, and a plurality of the subsidiary latching hooks 412are formed on the other edge of the drum door 400. The latching hooks411 and the subsidiary latching hooks 412 have an approximatelysemicircular shape.

In this embodiment, the drum door 400 is provided in the drum 300.Accordingly, the drum door 400 is movable in the circumferentialdirection along the inner circumferential surface of the drum 300 by thedriving unit 500,

The latching protrusions 331 and the subsidiary latching protrusions 332are protruded towards the inside of the drum 300, and the latching hooks411 and the subsidiary latching hooks 412 have a semicircular shape suchthat the surfaces of the latching hooks 411 and the subsidiary latchinghooks 412 facing the inside of the drum 300 are concaved.

Preferably, in addition to the above constitution, the washing machineof the present invention further comprises a weight 412 a provided onthe subsidiary latching hooks 412 for facilitating the opening andclosing of the drum door 400.

The weight 412 a separates the subsidiary latching hook 412 from thesubsidiary latching protrusion 332 by its own weight, when the drum 300is stopped. Further, the weight 412 a connects the subsidiary latchinghook 412 to the subsidiary latching protrusion 332 by the centrifugalforce, when the drum 300 is rotated, thereby firmly fixing the drum door400 to the opening 310 of the drum 300.

As shown in FIGS. 5 and 6, in this embodiment, since the drum door 400is provided in the drum 300, the drum driving shaft 320 having a hollowstructure for rotating the drum 300 is installed outside the doordriving shaft 520 for interconnecting the drum door 400 and the drivingmotor 510. Accordingly, the door driving shaft 520 passes through thedrum driving shaft 320 in the axial direction. First bearings 521 areinstalled between the door driving shaft 520 and the drum driving shaft320.

Further, second bearings 321 for rotatably fixing the drum 300 to thetub 200 are installed between the drum driving shaft 320 and the tub200.

The clutch unit 600 transmits the driving force of the driving unit 500to the drum driving shaft 320 so that the drum driving shaft 320 isrotated simultaneously with the rotation of the door driving shaft 520,when the washing machine is operated in washing and dehydration modes,and interrupts the transmission of the driving force of the drivingmotor 510 to the drum driving shaft 320, when the drum door 400 isopened.

For this reason, the clutch unit 600 is installed between the drivingmotor 510 and the drum driving shaft 320 such that the clutch unit 600moves in the axial direction of the drum driving shaft 320.

More specifically, the clutch unit 600 comprises a coupler 610 forselectively interconnecting the drum driving shaft 320 and the doordriving shaft 520, and a coupler driving portion for moving the coupler610.

The coupler 610 moves in the axial direction of the drum driving shaft320 by the coupler driving portion under the condition that the coupler610 is connected to the drum driving shaft 320 by serrations, and isselectively connected to the door driving shaft 520.

More preferably, when the drum door 400 is opened, one end of thecoupler 610 is separated from the door driving shaft 520 and the otherend of the coupler 610 is connected to one end of the tub 200.Accordingly, the coupler 610 interrupts the transmission of the drivingforce of the driving motor 510 to the drum 300, thereby preventing thechange of the position of the opening 310 of the drum 300.

For this reason, the coupler 610 comprises a first serration 611, asecond serration 612, and a third serration 613.

The first serration 611 is formed on one end of the coupler 610, and isselectively connected to a driving serration 510 a formed in the doordriving shaft 520.

The second serration 612 is engaged with a serration 320 a formed in thedrum driving shaft 320. Further, the third serration 613 is formed onthe other end of the coupler 610, and is selectively connected to afixing serration 220 formed in one end of the tub 200.

More specifically, the first serration 611 is formed on the innercircumferential surface of one end of the coupler 610, and is engagedwith the teeth-shaped driving serration 510 a formed in the outercircumferential surface of the door driving shaft 520 so as to rotatethe drum 300.

The second serration 612 is formed on the inner circumferential surfaceof the coupler 610, and is engaged with the serration 320 a formed inthe outer circumferential surface of the drum driving shaft 320.Thereby, the coupler 610 slides by means of the second serration 612engaged with the serration 320 a formed in the outer circumferentialsurface of the drum driving shaft 320.

The third serration 613 is engaged with the fixing serration 220 formedin one end of the tub 220 so as to prevent the rotation of the drum 300.

The coupler driving portion comprises at least one electromagnet 621 formoving the coupler 610 to control the interconnection between thecoupler 610 and the door driving shaft 520.

More specifically, the coupler driving portion comprises at least oneelectromagnet 621 formed on one of the tub 200 and the coupler 610, anda magnetic member 622 formed on the other one of the tub 200 and thecoupler 610 for moving the coupler 610 in one direction by theelectromagnetic interaction with the electromagnet 621.

The coupler driving portion further comprises an elastic member 623, oneend of which is supported by the coupler 610 and the other end of whichis supported by the rotor 512 of the driving motor 500.

The elastic member 623 moves the coupler 610 in the opposite directionof the movement of the coupler 610 by the magnetic member 622.

In this embodiment, the electromagnet 621 includes a solenoid fixed tothe tub 200 and having magnetic force by electrical energy applied fromthe outside, and the magnetic member 622 is fixed to the coupler 610.

The elastic member 623 includes a tension spring, which is supported bythe rotor 512 of the driving motor 500 and applies elastic force to thecoupler 610.

Instead of the above constitution of the coupler driving portiondescribed in the preferred embodiment, the coupler driving portion maybe variously modified.

By the above constitution of the coupler driving portion, the magneticmember 622 moves the coupler 610 towards the tub 200 when current isapplied to the electromagnet 621, cuts the interconnection between thecoupler 610 and the driving unit 500, and interconnects the coupler 610and one end of the tub 200, thereby preventing the rotation of the drumdriving shaft 320 when the drum door 400 is opened.

Hereinafter, the operation of the above drum washing machine of thepresent invention will be described in detail.

First, in the washing and dehydrating modes of the washing machine, anelectrical signal is not applied to the electromagnet 621.

Accordingly, as shown in FIG. 5, the coupler 610 moves towards the rotor512 by the force of the elastic member 623 so that the first serration611 is engaged with the driving serration 510 a of the door drivingshaft 520 and the second serration 612 is engaged with the serration 320a of the drum driving shaft 320.

When the rotor 512 of the driving motor 500 is rotated under the abovestate, the door driving shaft 520 and the drum driving shaft 320 aresimultaneously rotated, thereby rotating the drum 300 and the drum door400 in the same direction at the same speed.

Then, as shown in FIG. 3 and FIGS. 4A and 4B, the latching hooks 411 ofthe drum door 400 are latched onto the latching protrusions 331 of thedrum 300, and the subsidiary latching hooks 421 of the drum door 400 arelatched onto the subsidiary latching protrusions 332 of the drum 300 bythe centrifugal force of the weights 412 a, thereby preventing the drumdoor 400 from being separated from the opening 310 of the drum 300.

When a user manipulates an operation unit (not shown) formed on thecabinet 100 so that the drum door 400 is opened under the condition thatthe washing and dehydrating modes of the washing machine are terminatedor the operation of the washing machine is stopped, the driving motor510 is slowly driven to rotate the drum 300 until the sensing targetportion 710 is sensed by the position sensor 720.

When the sensing target portion 710 is sensed by the position sensor720, the operation of the driving motor 510 is stopped. Here, theopening 310 of the drum 300 is aligned to coincide with the opening 210of the tub 200.

Then, when current is applied to the electromagnet 621, theelectromagnet 621 generates magnetic force larger than the elastic forceof the elastic member 623. Thereby, the coupler 610 moves towards thetub 200 by the attractive force between the magnetic member 622 and theelectromagnet 621.

Thus, the first serration 611 is separated from the driving serration510 a of the door driving shaft 520, and the third serration 613 isengaged with the fixing serration 220 of the tub 200. In this case, thesecond serration 612 of the coupler 610 slides along the serration 320 aof the drum driving shaft 300, and then maintains its engaged state.

Accordingly, the drum 300 is restricted by the tub 200, and only thedoor driving shaft 520 is in a rotatable state.

When a control signal is applied to the driving motor 510 under theabove state, as shown in FIG. 7, the drum door 400 moves in thecircumferential direction of the drum 300, thereby opening the opening310 of the drum 300.

The above-described washing machine of the present invention has severaleffects, as follows.

First, a space occupied by the drum door for taking laundry into and outof the washing machine is minimized, and the drum door does not obstructthe taking of the laundry into and out of the washing machine.

Second, since the drum door is automatically opened and closed, thelaundry is conveniently taken into and out of the washing machine.

Third, since the alignment unit aligns the opening of the drum tocoincide with the opening of the tub, the reliability of operating thewashing machine is assured.

Fourth, since the drum and the drum door are driven by one motor and theclutch unit for selectively rotating the drum is prepared, the drum dooris smoothly opened and closed.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions.

Thus, it is intended that the present invention covers the modificationsand variations of this invention provided they come within the scope ofthe appended claims and their equivalents.

1. A washing machine comprising: a tub fixedly installed in a cabinet; adrum rotatably installed in the tub for containing laundry, and providedwith an opening formed through a cylindrical part thereof so that thelaundry is taken into and out of the drum through the opening; a drumdoor provided at the opening of the drum, and moving in the innercircumferential direction of the drum relative to the drum to open andclose the opening of the drum; a driving unit for rotating the drum, thedrum door being connected to the driving unit to automatically open theopening of the drum after finishing washing the laundry; and a clutchunit for selectively interconnecting the driving unit and the drum toselectively transmit driving force of the driving unit to the drum inwashing and dehydrating the laundry.
 2. The washing machine as set forthin claim 1, wherein the drum door rotates centering on a rotary axis ofthe drum to open and close the opening of the drum.
 3. The washingmachine as set forth in claim 1, wherein the driving unit comprises: adriving motor; and a door driving shaft, one end of which is connectedto a rotor of the driving motor and the other end of which is connectedto a rotary center of the drum door, to transmit the driving force ofthe driving motor to the drum door.
 4. The washing machine as set forthin claim 3, wherein the drum comprises a drum driving shaft, one end ofwhich is connected to a rotary center of the drum and the other end ofwhich is selectively connected to the driving unit by the clutch unit,and being concentric with the door driving shaft.
 5. The washing machineas set forth in claim 4, wherein the drum door is movable along theinner circumferential surface of the drum in the circumferentialdirection, and the door driving shaft passes through the drum drivingshaft in the axial direction.
 6. The washing machine as set forth inclaim 5, wherein the clutch unit is installed between the driving motorand the drum driving shaft such that the clutch unit moves in the axialdirection of the drum driving shaft, transmits the driving force of thedriving unit to the drum driving shaft so that the drum driving shaft isrotated simultaneously with the rotation of the door driving shaft, whenthe washing machine is operated in washing and dehydration modes, andinterrupts the transmission of the driving force of the driving motor tothe drum driving shaft, when the drum door is opened.
 7. The washingmachine as set forth in claim 5, wherein the clutch unit comprises: acoupler installed between the driving motor and the drum driving shaftsuch that the coupler moves in the axial direction of the drum drivingshaft, to selectively interconnect the drum driving shaft and the doordriving shaft; and a coupler driving portion for moving the coupler. 8.The washing machine as set forth in claim 7, wherein the coupler movesin the axial direction of the of the drum driving shaft by the couplerdriving portion under the condition that the coupler is connected to thedrum driving shaft by serrations, and is selectively connected to thedoor driving shaft.
 9. The washing machine as set forth in claim 8,wherein one end of the coupler is separated from the door driving shaftand the other end of the coupler is connected to one end of the tub sothat the position of the opening of the drum is not changed when thedrum door is opened.
 10. The washing machine as set forth in claim 9,the coupler comprises: a first serration formed on one end of thecoupler and selectively connected to a driving serration formed in thedoor driving shaft; a second serration engaged with a serration formedin the drum driving shaft; and a third serration formed on the other endof the coupler and selectively connected to a fixing serration formed inone end of the tub.
 11. The washing machine as set forth in claim 7,wherein the coupler driving portion comprises at least one electromagnetfor moving the coupler to control the interconnection between thecoupler and the door driving shaft.
 12. The washing machine as set forthin claim 7, wherein the coupler driving portion comprises: at least oneelectromagnet formed on one of the tub and the coupler; a magneticmember formed on the other one of the tub and the coupler for moving thecoupler in one direction by the electromagnetic interaction with theelectromagnet; and an elastic member, one end of which is supported bythe coupler and the other end of which is supported by the rotor of thedriving motor.
 13. The washing machine as set forth in claim 12, whereinthe magnetic member moves the coupler when current is applied to theelectromagnet, cuts the interconnection between the coupler and thedriving unit, and interconnects the coupler and one end of the tub so asto prevent the rotation of the drum driving shaft when the drum door isopened.
 14. The washing machine as set forth in claim 1, furthercomprising an alignment unit for aligning the opening of the drum tocoincide with an opening formed through the tub.
 15. The washing machineas set forth in claim 1, further comprising: at least one latchingprotrusion formed on one edge of the opening of the drum; and at leastone latching hook formed on one edge of the drum door and latched ontothe latching protrusion when the drum door is closed.
 16. The washingmachine as set forth in claim 15, further comprising: at least onesubsidiary latching protrusion formed on the other edge of the openingof the drum; and at least one subsidiary latching hook formed on theother edge of the drum door and latched onto the subsidiary latchingprotrusion.
 17. The washing machine as set forth in claim 16, whereinthe drum door is provided in the drum.
 18. The washing machine as setforth in claim 17, further comprising a weight provided on thesubsidiary latching hook for separating the subsidiary latching hookfrom the subsidiary latching protrusion by its own weight when the drumis stopped and connecting the subsidiary latching hook to the subsidiarylatching protrusion by the centrifugal force when the drum is rotated.